The propellers, which have a 200 to 300nm wide head and a one micron long tail arranged in a helical, corkscrew-like structure similar to that of a bacterial flagellum, can be induced to swim in a precise manner using a magnetic field.
The researchers used the propellers to push silica nanobeads 5 microns in diameter along precise, reproducible paths using a method that they believe could be used to steer similarly sized delivery particles in the bloodstream.
Peer Fischer, who co-authored the research with Ambarish Ghosh, told in-PharmaTechnologist that unlike “passive” nanoparticles that move by diffusion in the body the team’s technology can be actively “propelled and thereby steered.”
Dr Fischer explained that: “Our propellers are the smallest to date and the fabrication method we use is much simpler and permits propellers to be made on a very large scale and in large numbers.”
The team developed a technique that can produce about a billion propellers per square centimetre of a silicon dioxide substrate in around two hours.
“We used glass (silicon dioxide) but a number of other materials can be used and so this greatly enhances the utility of these propellers and permits the examination of chemical nature, and compatibility of these systems.”
Biocompatability studies required
He added that combining the active technology with “chemical attachment or use of a porous medium for the delivery of chemicals could be addressed, but clearly these applications require more basic research.”
“Silicon dioxide as a nanoparticle is for instance used in food additives, but as far as I know the FDA has not issued any directives regarding the use of nanoparticles. Use of nano/micro-particles will require biocompatibility studies.”
Despite these remaining hurdles Fischer said that the group “have received expressions of interest from industry… and are open to collaborations and proposals.”